PCA SDR

The new tech form should be ready for use.

http://www.pcasdr.org/porsche_events/prepare/forms/index.php


Let me know if you find any problems with it.

(Of course, please discontinue using the old one, it is now obsolete).

As a reminder, the rules: http://zone8.pca.org/rules.php

Not sure if this is where I should ask this but...

Section 3. E. has been reworded. Does this mean that I no longer have to take points on my '71 911E for changing from MECHANICAL INJECTION to CARBURETORS?

gocart wrote:Not sure if this is where I should ask this but...

Section 3. E. has been reworded. Does this mean that I no longer have to take points on my '71 911E for changing from MECHANICAL INJECTION to CARBURETORS?

Gordon-
That section reads:
III E. Induction system modification:
Electronic or CIS to carbs/mechanical injection and/or
Venturis or fuel distributor/controller other than original -- 4 pts.

I didn't think this wording changed--what is different? AFAIK, this 4-point penalty is for when you change from stock venturis in a carb'ed car to larger ones, or you change from a plenum-type, single-throttle-body injection system like CIS or the Motronic EFI to carbs or MFI (or an EFI with individual throttle-bodies for each cylinder). It should not apply to a car which changed from MFI to carbs alone. That is actually a downgrade and not a performance improvement. Most Porsche flat sixes that were built in both carb and MFI versions GAINED about 5-10 horsepower with the same displacement and had better throttle response in the MFI version. Changing from MFI to carbs was a convenience/economy move for owners who did not want to maintain the MFI system and is a downgrade, IMHO. It is not a performance improvement and should not be penalized by itself. However, if you have a custom engine where displacement is increased and larger carbs/venturis are installed than the original motor's MFI had, then it is appropriate to take the 4 points for induction, along with the increase in displacement, non-stock heads, cams, etc.

TT

The wording actually did change, but just slightly, and their was no intention of changing the meaning.

Anyway, if going from MFI to carbs falls under this umbrella:

fuel distributor/controller other than original

then it is 4 pts, regardless of whether it deserves it.

tb911 wrote:Anyway, if going from MFI to carbs falls under this umbrella:

fuel distributor/controller other than original

then it is 4 pts, regardless of whether it deserves it.

I think that rule needs clarification, then, Tom. If no other changes are made to the engine other than replacing a worn-out MFI system with carbs because you don't want to go to the expense of overhauling and tuning the MFI (which many owners did with the early cars, because it was simpler and cheaper to go to carbs), and the venturis are no bigger than the original MFi butterflies and ports are the same, there is no performance gain--the motor would probably lose a little power.

"Fuel distributor" and "controller" to me are terms specific to the CIS and Motronic systems, and aren't even applicable to the pre-73.5 911, by my way of thinking. I suppose you could say that MFI and/or carbs are "fuel controllers" but that's a stretch in my opinion. I certainly wouldn't protest anyone who had only changed from MFI to carbs and had not made any other changes to the engine and didn't take the 4 points.

TT

Obviously a gray area in the rules. In fact I had brought this up to the rules committee.

In my case I have a big bore 2.2 which now is a 2.5 liter in my '71E. It had mechanical injection originally. It now has 40 mm webers with 32 mm venturis. Does it matter that 32 mm venturis were original to some model of 911?

I have a couple of problems with the rules that are applied to the older cars.

First in Bruce Anderson's book there is a dino test that shows almost no increase in horsepower just by changing to larger venturis. So why is it a four point penalty to change to larger venturis? Obviously changing from CIS to carbs is a big advantage, four points seems fair for that.

Second do guys with newer cars take points for changing the motor's ECU? I don't think the rules are clear on that either.

gocart wrote:Second do guys with newer cars take points for changing the motor's ECU?

Good point. In the modern cars, the ECU is the "fuel controller." If changes are made to the stock fuel maps, then the car should take 4 points by the same sort of "broad" logic that says that carbs or MFI are "fuel controllers." This is impossible to see with the naked eye, and nearly impossible to police, however, so it gets little attention. We say that it is not allowed in S/S class, but I don't know how anyone could tell whether a chip had been reflashed without some highly technical equipment to read the code. Our classification and points methods are an "honor" system and easily abused.

TT

"Fuel distributor" and "controller" to me are terms specific to the CIS and Motronic systems

If that is the case, then you may be correct in your interpretation. Let me ask around.......

You should be ok, link should be correct

If you want to make sure, look in the lower right corner
Should say "T Brown Jan '10"